In an unprecedented response to the rapid decline in wild tiger populations, the Heads of Government of the 13 tiger range countries endorsed the St. Petersburg Declaration in November 2010, pledging to double the wild tiger population. We conducted a landscape analysis of tiger habitat to determine if a recovery of such magnitude is possible. The reserves in 20 priority tiger landscapes can potentially support >10,000 tigers, almost thrice the current estimate. However, most core reserves where tigers breed are small and land-use change in rapidly developing Asia threatens to increase reserve and population isolation. Maintaining population viability and resilience will depend upon a landscape approach to manage tigers as metapopulations. Thus, both site-level protection and landscape-scale interventions to secure habitat corridors are simultaneous imperatives. Co-benefits, such as payment schemes for carbon and other ecosystem services, should be employed as strategies to mainstream landscape conservation in tiger habitat into development processes.
Accelerated anthropogenic impacts and climatic changes are widely considered to be responsible for unprecedented species extinction. However, determining their effects on extinction is challenging owing to the lack of long-term data with high spatial and temporal resolution. In this study, using historical occurrence records of 11 medium- to large-sized mammal species or groups of species in China from 905 BC to AD 2006, we quantified the distinctive associations of anthropogenic stressors (represented by cropland coverage and human population density) and climatic stressors (represented by air temperature) with the local extinction of these mammals. We found that both intensified human disturbances and extreme climate change were associated with the increased local extinction of the study mammals. In the cold phase (the premodern period of China), climate cooling was positively associated with increased local extinction, while in the warm phase (the modern period) global warming was associated with increased local extinction. Interactive effects between human disturbance and temperature change with the local extinction of elephants, rhinos, pandas, and water deer were found. Large-sized mammals, such as elephants, rhinos, and pandas, showed earlier and larger population declines than small-sized ones. The local extinction sensitivities of these mammals to the human population density and standardized temperature were estimated during 1700 to 2000. The quantitative evidence for anthropogenic and climatic associations with mammalian extinction provided insights into the driving processes of species extinction, which has important implications for biodiversity conservation under accelerating global changes.
Many species have experienced dramatic declines over the past millennia due to the accelerated impact of human activity and climate change, but compelling evidence over such long‐term time scales is rare. China has a unique system archiving historical records of important social, meteorological, agricultural and biological events over the last three millennia. We derived historical species occurrences (0–2000 AD) based on a comprehensive review of literature. To detect the driving forces of range contraction, we used correlation and multiple regression to quantify the linear association between species range indices and climate variables (five temperature series and three precipitation series), as well as a human population size series. We also used a machine learning technique, random forest, to quantify the nonlinear effects of the climate variables and human population size. The southward retreat of the Asian elephant Elephas maximus and the rhinoceroses (Dicerorhinus sumatrensis, Rhinoceros unicornis, R. sondaicus) was closely associated with climate cooling and intensified human impact (represented by high population size), and the westward retreat of the giant panda Ailuropoda melanoleuca was associated with intensified human impact. One temperature series and human population size showed interactive effect on range shift of the Asian elephant and the rhinoceroses; the effect of temperature was positive at low population size, but negative at high population size. Our results imply that a higher temperature caused the northward or eastward range shift of the Asian elephant, the rhinoceroses and the giant panda, and currently this trend is impeded by human activities. We also illustrate how human activity and climate act synergistically to cause range contraction.
El Niño Southern Oscillation (ENSO) linked climate has been known to be associated with several rodent species, but its effects on rodent community at both spatial and temporal scales are not well studied. In this study, we investigated the possible causal chain relating ENSO, precipitation, temperature, and vegetation index (normalized difference vegetation index, NDVI) to rodent abundance for 14 sympatric rodent species in 21 counties of semiarid grasslands in Inner Mongolia, China, from 1982 to 2006. We found that both precipitation and temperature showed a generally direct positive effect on rodent abundance in many species in the current year, but indirect effects that operate through NDVI in the current or following year could have a reverse effect on abundance. We described one ENSO-linked precipitation bottom-up chain and three ENSO-linked temperature bottom-up chains. These observed bottom-up links reveal that in El Niño years, or 1 year after La Niña years, or 2 years after El Niño years, ENSO-driven climate or vegetation factors tend to increase population abundances of many sympatric rodent species in this region. We also found time-lag effects and the life-history strategy (i.e., functional groups of hibernating behavior, activity rhythm, or food habits) also contribute to the observed complicated effects of SOI on precipitation, temperature, NDVI, and ultimately rodent abundance.
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